The present invention relates to a tire condition monitoring system for providing tire operation parameter information, such as tire inflation pressure, to a vehicle operator and for providing tire location identification regardless of previous tire position change due to tire position rotation or the like. The present invention relates specifically to a tire condition monitoring system that provides for positive communication control between a vehicle-based unit and tire sensor units to avoid lost communication and the like.
Numerous tire condition monitoring systems have been developed in order to provide tire operation information to a vehicle operator. One example type of a tire condition monitoring system is a tire pressure monitoring system that detects when air pressure within a tire drops below a predetermined threshold pressure value.
There is an increasing need for the use of tire pressure monitoring systems due to the increasing use of xe2x80x9crun-flatxe2x80x9d tires for vehicles such as automobiles. A run-flat tire enables a vehicle to travel an extended distance after significant loss of air pressure within that tire. However, a vehicle operator may have difficulty recognizing the significant loss of air pressure within the tire because the loss of air pressure may cause little change in vehicle handling and little change in the visual appearance of the tire.
Typically, a tire pressure monitoring system includes a pressure sensing device, such as a pressure switch, an internal power source, and a communications link that provides the tire pressure information from a location at each tire to a central receiver unit. The central receiver unit is typically connected to an indicator or display located on a vehicle instrument panel.
The communications link between each tire-based unit and the central receiver unit is often a wireless link. In particular, radio frequency signals are utilized to transmit information from each of the tire-based units to the central receiver unit. However, in order for the central receiver unit to be able to properly associate/identify received tire pressure information with the tire associated with the transmission, some form of identification of the origin of the signal must be utilized. A need for identification of the origin of the transmitted tire information signal becomes especially important subsequent to a tire position change, such as tire position rotation during routine maintenance.
Along the lines of desiring uncorrupted and readily identified tire condition information, it is possible that the communications link between a tire-based unit and the central receiver may be disrupted. Such disruption may occur due to simultaneous communication from two tire-based units, multi-path interference from a single transmission, or rotating e-field created by tire movement.
Positive control of all of the communication that occurs within a system could have very desirable benefits, such as avoiding communication disruption or repeating disrupted communication. In particular, it may be desirable to have the positive control reside with the vehicle-based unit so that the vehicle-based unit may readily and reliably receive tire condition information. However, an ability of one unit to control another unit(s) is often thought of as being associated with the application and consumption of power (e.g., electrical power). In the marketplace of today, designs that incorporate high power consumption components are often rebuffed due to the cost of initial manufacture and/or the ongoing power use.
In accordance with one aspect, the present invention provides a tire condition sensor unit for association with a tire of a vehicle and for communicating a tire condition to a vehicle-based unit. Sensor means senses the tire condition. Transmitter means, operatively connected to the sensor means, transmits a condition signal that indicates the sensed tire condition. Receiver means, operatively connected to the sensor means and the transmitter means, receives a control signal and causes operation of the sensor means and the transmitter means during receipt of the control signal.
In accordance with another aspect, the present invention provides a tire condition sensor unit for association with a tire of a vehicle and for communicating a tire condition to a vehicle-based unit. Sensor means senses the tire condition. Transmitter means, operatively connected to the sensor means, transmits a condition signal that indicates the sensed tire condition. Receiver means, operatively connected to the sensor means and the transmitter means, receives a control signal and causes operation of the sensor means and the transmitter means during a predetermined time period.
In accordance with another aspect, the present invention provides a tire condition sensor unit for association with a tire of a vehicle and for communicating a tire condition to a vehicle-based unit. Sensor means senses the tire condition. Transmitter means, operatively connected to the sensor means, transmits a condition signal that indicates the sensed tire condition. Receiver means, operatively connected to the sensor means and the transmitter means, receives a control signal and causes operation of the sensor means and the transmitter means in response to receipt of the control signal. The receiver means includes means for amplifying strength of a received control signal.
In accordance with another aspect, the present invention provides a tire condition communication system for a vehicle. A tire condition sensing unit is operable to sense a tire condition and to transmit a signal indicative of the sensed condition. A vehicle-based unit receives the condition indicative signal. Communication means, which has a first portion associated with the vehicle-based unit and a second portion associated with the tire condition sensing unit, conveys a control signal from the vehicle-based unit to the tire condition sensing unit that causes the tire condition sensing unit to continue operation during conveyance of the control signal.
In accordance with another aspect, the present invention provides a method of communicating tire condition information from a tire condition sensor unit to a vehicle-based unit. A control signal is transmitted to a tire condition sensor unit. The control signal is received at the tire condition sensor unit. A condition is sensed at the tire. A signal indicative of the sensed condition is transmitted from the tire condition sensor unit so long as the control signal is received at the tire condition sensor unit.